https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87605
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Except A() is a temp so it cannot be a lvalue.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87605
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Except A() is a temp so it cannot be a lvalue.